BODY CONTROL MODULE (BCM) INSPECTION
2016 – MX-5 – Body and Accessories
BODY CONTROL MODULE (BCM) INSPECTION
1. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)
2. Remove the scuff plate (driver’s side). (See SCUFF PLATE REMOVAL/INSTALLATION.)
3. Remove the front side trim (driver’s side). (See FRONT SIDE TRIM REMOVAL/INSTALLATION.)
4. Remove the BCM. (See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION.)
5. Connect the BCM connector.
6. Connect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)
7. Verify that the voltages of each of the terminals are as indicated in the terminal voltage table (reference). (See Terminal Voltage Table (Reference).)
-
If the voltage is not as specified in the terminal voltage table (reference), inspect the parts under Inspection item(s) and related wiring harnesses.
-
If the system does not work normally even though the inspection items are normal, identify the malfunctioning location according to the directions in [DIAGNOSTIC SYSTEM] and [SYMPTOM TROUBLESHOOTING] then perform repairs.
Terminal Voltage Table (Reference)
|
Terminal |
Signal |
Connected to |
Measurement condition |
Voltage (V) |
Inspection item(s) |
|
|
1A |
Power supply |
HAZARD 15 A fuse |
Under any condition |
B+ |
HAZARD 15 A fuse |
|
|
1B |
Power supply |
|
Under any condition |
B+ |
|
|
|
1C |
— |
— |
— |
— |
— |
|
|
1D |
— |
— |
— |
— |
— |
|
|
1E |
Rear turn light (RH) control |
Rear turn light (RH) |
Ignition is switched ON (engine off or on) |
Turn switch is in right turn position |
1.0 or less ↔ B+ |
Rear turn light (RH) |
|
Turn switch is in position other than above |
1.0 or less |
|||||
|
1F |
— |
— |
— |
— |
— |
|
|
1G |
Rear turn light (LH) control |
Rear turn light (LH) |
Ignition is switched ON (engine off or on) |
Turn switch is in left turn position |
1.0 or less ↔ B+ |
Rear turn light (LH) |
|
Turn switch is in position other than above |
1.0 or less |
|||||
|
1H |
Interior light power supply |
Map light |
Under any condition |
B+ |
Map light |
|
|
1I |
— |
— |
— |
— |
— |
|
|
1J |
— |
— |
— |
— |
— |
|
|
1K |
Ground |
Body ground |
Under any condition |
1.0 or less |
Body ground |
|
|
1L |
Ground |
Body ground |
Under any condition |
1.0 or less |
Body ground |
|
|
2A |
Lock input (door lock-link switch (driver’s side)) |
Door latch and lock actuator (driver’s side) |
Driver’s door is locked |
1.0 or less |
Door latch and lock actuator (driver’s side) |
|
|
Driver’s door is unlocked |
Approx. 10 |
|||||
|
2B |
Unlock input (door lock-link switch (driver’s side)) |
Door latch and lock actuator (driver’s side) |
Driver’s door is locked |
Approx. 9.5 |
Door latch and lock actuator (driver’s side) |
|
|
Driver’s door is unlocked |
1.0 or less |
|||||
|
2C |
CAN_L |
CAN system related module |
Terminal used for communication therefore determination based on terminal voltage is not possible. |
|||
|
2D |
CAN_H |
CAN system related module |
Terminal used for communication therefore determination based on terminal voltage is not possible. |
|||
|
2E |
Top lock switch signal |
Top lock switch |
Convertible top is open |
1.0 or less |
Top lock switch |
|
|
Convertible top is closed |
Approx. 9.5 |
|||||
|
2F |
— |
— |
— |
— |
— |
|
|
2G |
Door latch switch (passenger’s side) signal |
Door latch and lock actuator (passenger’s side) |
Door (passenger’s side) is open |
1.0 or less |
Door latch and lock actuator (passenger’s side) |
|
|
Door (passenger’s side) is closed |
Approx. 9.0 |
|||||
|
2H |
Door latch switch (driver’s side) signal |
Door latch and lock actuator (driver’s side) |
Door (driver’s side) is open |
1.0 or less |
Door latch and lock actuator (driver’s side) |
|
|
Door (driver’s side) is closed |
Approx. 9.5 |
|||||
|
2I |
— |
— |
— |
— |
— |
|
|
2J |
Serial communication |
Start stop unit |
Terminal used for communication therefore determination based on terminal voltage is not possible. |
|||
|
2K*1 |
Door lock switch signal |
Door lock switch (RH) |
Door lock switch is turned to unlock side (driver’s side or passenger’s side) |
1.0 or less |
Door lock switch (RH) |
|
|
Door lock switch is turned to lock side (driver’s side or passenger’s side) |
Approx. 1.25 |
|||||
|
Other |
Approx 5.0 |
|||||
|
2L |
Door key cylinder switch signal |
Door latch and lock actuator (driver’s side) |
Door key cylinder is turned to unlock side |
1.0 or less |
Door latch and lock actuator (driver’s side) |
|
|
Door key cylinder is turned to lock side |
Approx. 1.25 |
|||||
|
Other |
Approx 5.0 |
|||||
|
2M*2 |
Lock input (door lock-link switch (passenger’s side)) |
Door latch and lock actuator (passenger’s side) |
Passenger’s door is unlocked |
1.0 or less |
Door latch and lock actuator (passenger’s side) |
|
|
Passenger’s door is locked |
B+ |
|||||
|
2N |
— |
— |
— |
— |
— |
|
|
2O |
— |
— |
— |
— |
— |
|
|
2P |
— |
— |
— |
— |
— |
|
|
2Q |
Fuel sensor signal |
Fuel gauge sender unit |
Inspect fuel gauge sender unit and related wiring harness because determination based on terminal voltage is not possible. |
|||
|
2R |
Fuel sensor ground |
Fuel gauge sender unit |
Under any condition |
1.0 or less |
Fuel gauge sender unit |
|
|
2S |
Trunk lid unlatch switch signal (exterior) |
Trunk lid opener switch (exterior) |
Trunk is opened |
1.0 or less |
Trunk lid opener switch (exterior) |
|
|
Trunk is closed |
Approx. 4.5 |
|||||
|
2T |
— |
— |
— |
— |
— |
|
|
2U |
— |
— |
— |
— |
— |
|
|
2V |
— |
— |
— |
— |
— |
|
|
2W |
— |
— |
— |
— |
— |
|
|
2X |
— |
— |
— |
— |
— |
|
|
2Y |
LIN communication |
Electrical supply unit (ESU) |
Terminal used for communication therefore determination based on terminal voltage is not possible. |
|||
|
2Z |
— |
— |
— |
— |
— |
|
|
2AA |
— |
— |
— |
— |
— |
|
|
2AB |
— |
— |
— |
— |
— |
|
|
2AC |
Trunk lid latch switch signal |
Trunk lid latch and release actuator |
Trunk is opened |
1.0 or less |
Trunk lid latch and release actuator |
|
|
Trunk is closed |
Approx. 9.5 |
|||||
|
2AD |
— |
— |
— |
— |
— |
|
|
2AE |
— |
— |
— |
— |
— |
|
|
2AF |
— |
— |
— |
— |
— |
|
|
3A |
Front turn light (RH) control |
Front turn light (RH) |
Ignition is switched ON (engine off or on) |
Turn switch is in right turn position |
1.0 or less ↔ B+ |
Front turn light (RH) |
|
Turn switch is in position other than above |
1.0 or less |
|||||
|
3B |
Front turn light (LH) control |
Front turn light (LH) |
Ignition is switched ON (engine off or on) |
Turn switch is in left turn position |
1.0 or less ↔ B+ |
Front turn light (LH) |
|
Turn switch is in position other than above |
1.0 or less |
|||||
|
3C |
CAN_H |
CAN system related module |
Terminal used for communication therefore determination based on terminal voltage is not possible. |
|||
|
3D |
CAN_L |
CAN system related module |
Terminal used for communication therefore determination based on terminal voltage is not possible. |
|||
|
3E |
Blower motor relay control |
|
Ignition is switched ON (engine off or on) |
Blower motor is operated using fan switch |
1.0 or less |
|
|
Blower motor is turned off by pressing climate control unit OFF button |
B+ |
|||||
|
3F |
Windshield wiper INT relay control |
Wiper INT relay |
Ignition is switched ON (engine off or on) |
Windshield wiper switch is in position other than OFF |
1.0 or less |
Wiper INT relay |
|
Windshield wiper switch is in OFF position |
B+ |
|||||
|
3G |
Windshield wiper motor (HI) control |
Wiper HI relay |
Ignition is switched ON (engine off or on) |
Windshield wiper switch is in HIGH position |
1.0 or less |
Wiper HI relay |
|
Windshield wiper switch is in OFF position |
B+ |
|||||
|
3H |
Horn relay control |
Horn relay |
Ignition is switched ON (engine off or on) |
Horn switch is on |
1.0 or less |
Horn relay |
|
Horn switch is off |
B+ |
|||||
|
3I |
— |
— |
— |
— |
— |
|
|
3J |
— |
— |
— |
— |
— |
|
|
3K |
Rear window defogger relay control |
Rear window defogger relay |
Ignition is switched ON (engine off or on) |
Rear window defogger switch is on |
1.0 or less |
Rear window defogger relay |
|
Rear window defogger switch is off |
B+ |
|||||
|
3L |
— |
— |
— |
— |
— |
|
|
3M |
Autostop switch signal |
Wiper motor |
Ignition is switched ON (engine off or on) |
Wiper switch is on and wiper is operating |
1.0 or less |
Wiper motor |
|
Wiper switch is off |
B+ |
|||||
|
3N |
Power supply |
|
Under any condition |
B+ |
|
|
|
3O |
Ignition power supply |
METER1 10 A fuse |
Ignition is switched ON (engine off or on) |
B+ |
METER1 10 A fuse |
|
|
The ignition is switched off (LOCK) |
1.0 or less |
|||||
|
3P |
— |
— |
— |
— |
— |
|
|
3Q*3 |
Washer fluid level sensor signal |
Washer fluid level sensor |
Ignition is switched ON (engine off or on) |
Washer fluid level sensor is less than MIN (washer fluid level sensor on) |
1.0 or less |
Washer fluid level sensor |
|
Washer fluid level sensor is MIN or more (Washer fluid level sensor off) |
B+ |
|||||
|
3R |
Brake fluid level sensor signal |
Brake fluid level sensor |
Ignition is switched ON (engine off or on) |
Brake fluid level sensor is less than MIN (brake fluid level sensor on) |
1.0 or less |
Brake fluid level sensor |
|
Brake fluid level sensor is MIN or more (brake fluid level sensor off) |
B+ |
|||||
|
3S |
— |
— |
— |
— |
— |
|
|
3T |
Horn switch control |
Horn switch |
Ignition is switched ON (engine off or on) |
Horn switch is on (long press) |
1.0 or less |
Horn switch |
|
Horn switch is off |
B+ |
|||||
|
3U |
Trunk unlatch switch signal (interior) |
Trunk lid opener switch (interior) |
Trunk lid opener switch (interior) is on (trunk lid opener switch (interior) is pressed) |
1.0 or less |
Trunk lid opener switch (interior) |
|
|
Trunk lid opener switch (interior) is off (trunk lid opener switch (interior) is not pressed) |
B+ |
|||||
|
3V |
— |
— |
— |
— |
— |
|
|
3W*5 |
Hood latch switch signal |
Hood latch switch |
Hood is open |
Approx. 9.0 |
Hood latch switch |
|
|
Hood is closed |
1.0 or less |
|||||
|
3X |
LIN communication |
Auto-light sensor/rain sensor*4 |
Terminal used for communication therefore determination based on terminal voltage is not possible. |
|||
- *1
- With door lock switch
- *2
- With front fog light
- *3
- With washer fluid level sensor
- *4
- With auto light system/auto wiper system
- *5
- With hood latch switch